JP7398606B2 - Hybrid methods of forming microstructure array molds, methods of making microstructure arrays, and methods of use - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62/689,640, filed June 25, 2018, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD This disclosure generally relates to methods for making or fabricating molds for making microstructure arrays, methods of using molds to make microstructure arrays, and related features thereof.

Background Arrays of microneedles were proposed as a method of administering drugs through the skin in the 1970s, for example in expired US Pat. No. 3,964,482. Microneedles, microprotrusions, or microstructure arrays may facilitate the passage of drugs through or into human skin and other biological membranes in situations where conventional transdermal administration is inappropriate. I can do it. Microstructure arrays can also be used to sample fluids found in the vicinity of biological membranes, such as interstitial fluid, which are then tested for the presence of biomarkers.

In recent years, it has become more viable to produce microstructure arrays in a manner that makes their widespread use financially viable. US Pat. No. 6,451,240 discloses several methods of manufacturing microneedle arrays. If the array is sufficiently inexpensive, it may be commercially available, for example, as a disposable device. Disposable devices avoid the possibility that the integrity of the device has been compromised by previous use, and avoid the potential need to sterilize the device and maintain it in controlled storage after each use. Therefore, it may be preferable to be reusable.

Despite much initial work fabricating microneedle arrays in silicon or metal, there are significant advantages to polymer arrays. US Pat. No. 6,451,240 discloses several methods of manufacturing polymeric microneedle arrays. Arrays made primarily of biodegradable polymers also have several advantages. US Pat. No. 6,945,952 and US Pat. A further description of the fabrication of microneedle arrays made from polyglycolic acid is provided by Jung-Hwan Park et al. "Biodegradable polymer microneedles: Fabrication, mechanics, and transdermal drug delivery", J. of Controlled Release, 104:51-66 (2005).

Conventional micromolding techniques have been used to fabricate molds for forming microprotrusion arrays (Park et al., Biomed Microdevices, 2007, 9(2):223-234). A method for fabricating microneedles using photolithographic and soft lithographic techniques is described in US Pat. No. 7,763,203. However, conventional micromolding and lithography techniques have limitations when producing complex microstructure structures and shapes.

A method of forming microprotrusion arrays using a solvent casting method is described in US Patent Application Publication No. 2008/0269685, incorporated herein by reference in its entirety. These arrays are formed using ceramic, metal, or polymer molds in which the material for the microprotrusion array is cast onto the mold.

Despite these efforts, there remains a need to find simpler and better methods for manufacturing polymeric delivery systems. One problem with the present mold is that it is difficult to prepare a mold with the desired shape for the microprotrusions. One particular need is the production of a simple method for forming microstructure array molds. A further need is the manufacture and use of molds that reduce or eliminate the need for extensive machining of arrays formed in molds.

The foregoing examples of related art and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those skilled in the art upon reading the specification and examining the drawings.

U.S. Patent No. 3,964,482 US Patent No. 6,451,240 US Patent No. 6,451,240 US Patent No. 6,945,952 US Patent Application Publication No. 2002/0082543 US Patent Application Publication No. 2005/0197308 US Patent No. 7,763,203 US Patent Application Publication No. 2008/0269685

Jung-Hwan Park et al. "Biodegradable polymer microneedles: Fabrication, mechanics, and transdermal drug delivery", J. of Controlled Release, 104:51-66 (2005) Park et al. , Biomed Microdevices, 2007, 9(2):223-234

BRIEF SUMMARY The following aspects and embodiments thereof described and illustrated below are intended to be exemplary and illustrative rather than limiting in scope.

In one aspect, a method of forming a master mold is provided. In some embodiments, a master mold is provided for use in preparing or forming a microstructure array. In some embodiments, the method includes: a) forming a plurality of micromachined parts into a substrate formed from a first material by a first micromachining process, each comprising a shaft portion and a distal tip section; forming a microstructure; and b) preparing a mold for the plurality of microstructures formed in a), such that the mold includes a negative portion of the plurality of microstructures; the mold is formed from a second material; c) electroplating metal onto the mold to fill cavities in the mold and create a base layer; e) a second material. f) forming a proximal section for each of the microstructures in the base layer using a micromachining process of; f) removing a second material from the metal to form a master mold; including. In embodiments, the second micromachining process is a mechanical micromachining process. In some embodiments, the first micromachining process includes a photolithography process. In some embodiments, the first material is selected from silicon and a positive photoresist material. In some embodiments, the second material is a polymeric material. In some embodiments, the polymeric material is selected from the group consisting of polydimethylsiloxane (PDMS), polycarbonate, polyetherimide, polyethylene terephthalate, or mixtures thereof.

In some embodiments, the electroplated metal is selected from copper, nickel, chromium, and/or gold.

In some embodiments, a photolithographic method includes the steps of: 1) applying a layer of photoresist on a first material; and 2) applying a masking material on the photoresist layer, the masking material comprising: 3) curing portions of the photoresist layer not covered by the masking material; and 4) isotropically etching the substrate to define the distal tip section. 5) etching the substrate to create a shaft portion; 6) wet thermally oxidizing the microstructure; and 7) isotropically wet etching the microstructure. In embodiments, the first material is silicon. In some embodiments, the photolithography method includes, prior to step 1, forming a layer of silicon dioxide on the silicon substrate using a thermal oxidation process. In some embodiments, the thermal oxidation process in step 1 is a wet thermal oxidation process. In some embodiments, the photoresist material is an epoxy-based negative photoresist. In some embodiments, the photoresist material is SU8. In some embodiments, the masking material comprises a plurality of apertures and the photoresist layer exposed by the apertures is cured in step 3.

In some embodiments, the photolithographic method further includes removing the masking material and any uncured photoresist material after step 3, e.g., after curing the portions of the photoresist layer not covered by the masking material. Contains steps. In some embodiments, the masking material and uncured photoresist are removed using a solvent. In some embodiments, the etch is an anisotropic etch, a deep reactive ion etch, and/or a plasma etch. In some embodiments, the plasma etch includes a plasma gas selected from at least one of SF ₆ , carbon tetrachloride, oxygen, and CHF ₃ .

In another aspect, a method of forming a casting mold is provided. In embodiments, a negative mold of the master mold is prepared.

In another aspect, a method of preparing a microstructure array is provided. In some embodiments, the method includes the steps of: dispensing a polymer matrix solution or suspension containing at least one therapeutic agent onto a casting mold; drying the polymer matrix solution; dispensing a polymer matrix backing solution onto a rolling mold; drying the polymer matrix backing solution to form a microstructure array; and demolding the resulting microstructure array. .

Additional embodiments of the present molds, microstructures, arrays, methods, apparatus, devices, and the like will be apparent from the following description, drawings, examples, and claims. As can be understood from the foregoing and following description, any and all features described herein, as well as any and all combinations of two or more of such features, are intended only to the extent that the features included in such combinations are not mutually exclusive. provided that it is within the scope of this disclosure. Additionally, any feature or combination of features may be specifically excluded from any embodiment of the invention. Additional aspects and advantages of the invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying examples and drawings.
The present invention provides, for example, the following.
(Item 1)
A method of forming a master mold, the method comprising:
a) forming a plurality of microstructured portions in a substrate formed from a first material by a first micromachining process, each microstructured portion comprising a shaft and a distal tip; , step and
b) preparing a negative mold for the plurality of microstructured portions, the mold being formed from a second material and comprising a plurality of negative molds corresponding to each microstructured portion within the plurality of microstructured portions; a step comprising a cavity;
c) electroplating metal onto the negative mold to form a base layer that fills each cavity in the plurality of cavities and extends from the negative mold;
d) forming a proximal section for each of the microstructures in the base layer using a second micromachining process;
e) before or after step d), removing the negative mold from the metal to form a master mold;
method including.
(Item 2)
2. The method of item 1, wherein the second micromachining process is a mechanical micromachining process.
(Item 3)
3. A method according to item 1 or item 2, wherein the first material is selected from silicon and a positive photoresist material.
(Item 4)
The method according to any one of items 1 to 3, wherein the first micromachining process comprises a photolithography process.
(Item 5)
The photolithography includes:
1) applying a layer of photoresist on the first material;
2) applying a masking material onto the photoresist layer, the masking material covering at least a portion of the photoresist layer;
3) curing portions of the photoresist layer not covered by the masking material;
4) isotropically etching the substrate to create a distal tip section;
5) etching the substrate to create a shaft portion;
6) Wet thermal oxidation of the microstructure;
7) isotropically wet etching the microstructure;
The method according to item 4, comprising:
(Item 6)
6. The method of claim 5, wherein the first material is silicon, and the method further comprises forming a layer of silicon dioxide on the silicon substrate using a thermal oxidation process prior to step 1. Method.
(Item 7)
6. The method according to item 5, wherein the thermal oxidation process in step 1 is a wet thermal oxidation process.
(Item 8)
6. The method of item 5, wherein the photoresist material is an epoxy-based negative photoresist.
(Item 9)
9. The method of item 8, wherein the photoresist material is SU8.
(Item 10)
6. The method of item 5, wherein the masking material comprises a plurality of apertures and the photoresist layer exposed by the apertures is cured in step 3.
(Item 11)
6. The method of item 5, further comprising removing the masking material and any uncured photoresist material after step 3.
(Item 12)
12. The method of item 11, wherein the masking material and uncured photoresist are removed using a solvent.
(Item 13)
6. The method of item 5, wherein the etching in step 5 comprises anisotropic etching.
(Item 14)
The method of item 5, wherein step 5 comprises deep reactive ion etching.
(Item 15)
6. The method of item 5, further comprising washing the polymeric material prior to step 1.
(Item 16)
16. The method of item 15, wherein the cleaning includes chemical cleaning.
(Item 17)
17. The method of item 16, wherein the chemical cleaning comprises an RCA cleaning process.
(Item 18)
6. The method of item 5, wherein step 4 and/or step 5 comprises plasma etching.
(Item 19)
19. The method of item 18, wherein the plasma etching comprises a plasma gas selected from _SF6 , carbon tetrachloride, oxygen, and CHF3 _.
(Item 20)
6. The method of item 5, further comprising removing any remaining photoresist from the first material after step 5.
(Item 21)
A method according to any of the preceding items, wherein the second material is a polymeric material.
(Item 22)
A method according to any of the preceding items, wherein the second material is a silicone material.
(Item 23)
22. The method of item 21, wherein the second polymeric material is selected from the group consisting of polydimethylsiloxane (PDMS), polycarbonate, polyetherimide, and polyethylene terephthalate.
(Item 24)
A method according to any of the preceding items, wherein the electroplated metal is selected from copper, nickel, chromium, and gold.
(Item 25)
A method according to any of the preceding items, wherein the proximal section is micromachined to have a funnel or pyramidal shape.
(Item 26)
A method of forming a casting mold, the method comprising:
A method comprising preparing a negative mold of the master mold formed in any one of items 1-25.
(Item 27)
1. A method of preparing a microstructure array, the method comprising:
dispensing a polymer matrix solution or suspension containing at least one therapeutic agent onto the casting mold of item 26;
drying the polymer matrix solution;
dispensing a polymer matrix backing solution onto the casting mold;
drying the polymer matrix backing solution to form the microstructure array;
demolding the microstructure array;
including methods.

1A-1K are illustrations of certain embodiments of methods of forming molds that are useful for manufacturing microstructure arrays.

FIG. 2 is an illustration of an embodiment of a method of forming a mold that is useful for manufacturing microstructure arrays.

3A-3D are illustrations of microstructure shapes, according to some embodiments.

FIG. 4 is an illustration of a method of forming a microstructure array using a mold described herein, according to one embodiment.

FIG. 5 is a flowchart of a method for preparing a microarray mold and microprotrusion array from a mold, according to one embodiment.

It should be appreciated that the thickness and shape of various microstructures are exaggerated in the figures to facilitate understanding of the device. Drawings are not necessarily "to scale."

Various aspects will now be described more fully below. However, such aspects may be embodied in many different forms and should not be construed as limitations on the embodiments described herein; rather, these embodiments may be embodied in many different forms. , is provided to be exhaustive and complete, and to fully convey its scope to those skilled in the art.

DETAILED DESCRIPTION The practice of the present disclosure will employ, unless otherwise indicated, conventional methods of chemistry, biochemistry, and pharmacy, within the skill of the art. Such techniques are fully explained in the literature. For example, A. L. Lehninger, Biochemistry (Worth Publishers, Inc. (current edition)), Morrison and Boyd, Organic Chemistry (Allyn and Bacon, Inc. (current edition)), J. March, Advanced Organic Chemistry (McGraw Hill (current edition)), Remington: The Science and Practice of Pharmacy, A. Gennaro (20th ed.), Goodman & Gilman The Pharmacological Basis of Therapeutics, J. Griffith Hardman, L. L. Limbird, A. See Gilman (10th ed.).

When a range of values is provided, each intervening value between the upper and lower limits of that range and any other stated or intervening value within that stated range is intended to be encompassed within this disclosure. intended. For example, if a range from 1 μm to 8 μm is mentioned, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, and 7 μm are also included, as well as a range of values greater than or equal to 1 μm and a range of values less than or equal to 8 μm. expressly intended to be disclosed.

As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "polymer" includes a single polymer as well as two or more of the same or different polymers; reference to an "excipient" includes a single excipient as well as two or more of the same or different polymers; including two or more of the excipients, etc.

In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set forth below.

The term "about" when immediately preceding a numerical value means a range of ±10% of that value, unless the context of this disclosure clearly indicates otherwise or is inconsistent with such interpretation. For example, "about 50" means 45 to 55, "about 25,000" means 22,500 to 27,500, and so on. For example, in a numerical enumeration such as "about 49, about 50, about 55," "about 50" means a range extending less than half the interval between the immediately preceding value and the subsequent value, e.g., greater than 49.5. - means less than 52.5. Additionally, the phrases "less than about" or "greater than about" are to be understood in light of the definition of the term "about" provided herein.

The terms "microprotrusion," "microprotrusion," "microstructure," and "microneedle" are used interchangeably herein to penetrate or penetrate at least a portion of the stratum corneum or other biological membrane. Refers to an element adapted to puncture. For example, exemplary microstructures, in addition to those provided herein, include microblades as described in U.S. Patent No. 6,219,574, microblades as described in U.S. Patent No. 6,652,478, and and microprotrusions as described in US Patent Publication No. 2008/0269685.

The term "microstructure array" for purposes herein is intended to refer to a two-dimensional or three-dimensional array of microstructures, microprotrusions, microprotrusions, or microneedles. The arrangement may be regular according to a repeating geometric pattern, or it may be irregular. A typical "microstructure array," "microprotrusion array," or "microneedle array" includes microstructures, microprotrusions, or microneedles protruding from a base or substrate of a specified thickness, which include: It may be of any shape, for example square, rectangular, triangular, oval, circular, or irregular. An array typically comprises a plurality of microstructures, microprotrusions, or microneedles. Microstructures, microprotrusions, or microneedles may themselves have a variety of shapes. The array may be pressed into the skin by hand to hold the array as it is applied, and/or to the skin or other biological membrane in one way or another. Various devices may be used to facilitate the process of applying the array. Such devices may be broadly referred to as "applicators." The applicator can reduce force, velocity, and skin tension variations that occur, for example, when the array is pressed into the skin by hand. Variations in force, speed, and skin tension can result in variations in permeability enhancement.

When discussing the applicators and arrays described herein, the term "downward" is sometimes used to describe the direction in which microstructures are pressed into the skin, and "upward" is used to describe the direction in which the microstructures are pressed into the skin. Used to describe opposite directions. However, the person skilled in the art will appreciate that the applicator can also be used where the microstructures are pressed into the skin at an angle, in the direction of the Earth's gravity, or even in a direction opposite to that of the Earth's gravity. You will understand that. In many applicators, the energy for injecting microstructures is primarily provided by the energy storage member, so efficiency is largely unaffected by the orientation of the skin relative to Earth's gravity.

"Biodegradable" means a natural or synthetic material that breaks down enzymatically, non-enzymatically, or both, producing biocompatible and/or toxicologically safe by-products that can be eliminated by normal metabolic pathways. refers to The term "biodegradable" is intended to include those materials that involve the processes of erosion, dissolution, disintegration, and degradation, and are often referred to as bioerodible or biodegradable. intend.

"Non-biodegradable" is perceivable when inserted into and/or contacted with skin, mucous membranes, or other biological membranes over a period of time associated with the use of microstructure arrays. Refers to natural or synthetic materials that do not degrade to a high degree. In some embodiments, "non-biodegradable" refers to skin, for a period of at least about 5 minutes, about 10 minutes, about 15 minutes, about 20 minutes, about 30 minutes, about 1 hour, or more. Refers to a material that does not appreciably degrade when inserted into and/or contacted with mucous membranes or other biological membranes. The term "non-biodegradable" is also intended to include the processes of erosion, dissolution, and disintegration.

"Optional" or "at will" means that the subsequently described situation may or may not occur, such that the explanation includes instances where the situation occurs and instances where it does not.

In this application, for convenience, we often refer to "skin" as the biological membrane penetrated by microstructures. In most or all cases, the same principles of the invention may be applied to microstructures for penetrating other biological membranes, such as those lining the inside of the mouth or those exposed during surgical procedures. It will be understood by those skilled in the art that it also applies to the use of

"Substantially" or "essentially" means almost entirely or completely, eg, 90-95% or more of a given amount.

"Transdermal" refers to the delivery of drugs into and/or through the skin for local and/or systemic therapy. or other body tissues that line the mouth, gastrointestinal tract, blood-brain barrier, or that are exposed or accessible during surgery or procedures such as laparoscopy or endoscopy. Administration through other biological membranes, such as organs or biological membranes, is also contemplated as a surface on which the microstructures described herein will find use.

A material that is "water-soluble" is one that is soluble or substantially soluble in an aqueous medium such that the material dissolves in, within, or under skin or other membranes that are substantially aqueous in nature. Intended for materials that are soluble.

Compositions of the present disclosure can include, consist essentially of, or consist of the disclosed components.
I. How to make microstructure array molds

Before describing the manufacturing method in detail, it is to be understood that the method is not limited to specific solvents, materials, or device structures, which may vary accordingly. Additionally, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

Generally, arrays of microstructures, or portions thereof, are formed of materials such as silicon or photoresist using semiconductor microfabrication techniques. The negative mold of the microstructure array (section) may be formed from silicone or other suitable material. The micromachined portion is removed and electroforming techniques are used to fill the cavity with a suitable metal. Additional sections of metal are electroformed to create a base for preparing the proximal portion of the microstructure. Additional sections are micromachined to create the desired shape for the proximal portion of the microstructure. The present positive mold may be used as a master mold suitable for use in creating one or more negative molds. These negative molds can then be used in the step of casting the microstructure array for use.

The molds used to form the arrays herein can be made using a variety of methods and materials. In one common method, a master mold is prepared for use in creating the microstructure array. A master mold may be formed by creating a positive master mold, which is then used to form a negative mold. The master mold can be used to prepare a casting mold to prepare the microstructure array for use. In certain embodiments, the method includes the steps of: (i) forming a positive mold of at least a portion of the structure of the microstructure; (ii) forming a negative mold from the positive mold of (i); (iii) preparing a second positive mold comprising structures of microstructures; and (iv) micromachining the second positive mold to form a master mold with microstructures having a desired shape. and forming a hybrid method. In one embodiment, the step is identified by (i) forming a positive mold of at least a portion of the structure of the microstructure, the step of forming a positive mold of the distal tip and shaft portion of the microstructure. including. In one embodiment, electroforming the negative mold, filling the cavities of the positive mold, identified by (iii) preparing a second positive mold comprising the microstructured structure; creating a base layer extending from a negative mold; In one embodiment, the step of micromachining the second positive mold comprises micromachining the base layer extending from the negative mold into the desired shape of the base portion of each microstructure, identified by (iv) micromachining the second positive mold. micromachining into a funnel shape or other shape corresponding to.

Generally, the method of fabricating molds is a hybrid method involving micromachining, lithography, and mold casting to form a master mold, a cast mold, and/or a microstructure array. Generally, microfabrication methods, such as semiconductor microfabrication methods, are used to form at least the distal portion of the microstructure mold. Semiconductor micromachining is used to form at least the distal portion or sharp tip of the microstructure. One such microfabrication method is illustrated generally in FIGS. 1A-1K. Generally, semiconductor microfabrication methods use a combination of photolithography and etching to create the desired shape. Other methods and/or materials, such as those known and/or used in microelectronic processing, including, but not limited to, semiconductor processing, may be used in or associated with the methods described below. It should be understood that it may be incorporated.

Referring to FIGS. 1A-1K, an exemplary semiconductor micromachining process for preparing a distal portion or tip of a microstructured master mold is shown. It should be appreciated that other steps or steps in a different order may also be used to create the distal portion or tip of the microstructure.

A substrate 10 is provided, formed from a suitable material. The substrate may be formed from any material suitable for use with photolithographic techniques. In non-limiting embodiments, the substrate is formed from silicon or a positive photoresist material. In some embodiments, the substrate is formed from glass, including, but not limited to, borosilicate glass or sapphire glass, such as PYREX® (Corning). In one embodiment, the positive photoresist material becomes soluble to a photoresist stripper or developer upon exposure to light or certain wavelengths of light. As an initial step, the substrate may be cleaned using any method known in the art. It should be appreciated that the method of cleaning a substrate may depend on the composition of the substrate. In one embodiment where the substrate is formed from silicon, the substrate may be cleaned by RCA cleaning methods as known in the art. In embodiments, the substrate may be treated or coated with one or more materials. For example, the substrate may be coated with a material that modulates or assists in photolithography or etching processes. In one embodiment, the substrate is coated with an anti-reflection coating or a coating that adjusts or improves the angle of light used in subsequent steps. In another embodiment, if the substrate is a silicon substrate, a layer of an oxide, such as silicon dioxide, may be formed on the substrate 10 by a suitable process prior to photoresist coating. One exemplary process is a thermal oxidation procedure, such as wet thermal oxidation.

The microstructured tip may be formed using any suitable photolithographic technique as known in the art. In one embodiment, a layer of negative photoresist 12 is added to the top or exposed surface of substrate 10 (step (a)). One suitable photoresist is an epoxy-based photoresist such as SU-8 (Microchem). As a photoresist, SU-8 can produce film thicknesses of 30 microns or more (eg, from about 0.5 μm to >200 μm thick in a single coating). It should be understood that other materials as known in the art may also be used as photoresists. Additionally, other photoresist materials or otherwise light- and/or radiation-sensitive materials may be used to create a photoresist thickness of less than or greater than about 30 microns on the substrate. The photoresist can be applied by spin coating or otherwise applied or spread to the desired thickness across the substrate. In embodiments, the photoresist may be deposited or applied to a thickness ranging from about 1 micron to about 300 microns, or about 5 microns to about 500 microns, or about 10 microns to about 275 microns.

A masking material 14 is placed over at least a portion of the photoresist material (step (b)). Any suitable masking material as known in the art may be used. In embodiments, the masking material may be a photoresist that is patterned using photolithographic techniques. In other embodiments, the masking material may be a coated glass or quartz plate with the desired pattern imprinted on it. In other embodiments, the masking material may be a coating as known in the art, including, but not limited to, silicon dioxide or Si ₃ N ₄ . The masking material may include one or more apertures, openings, patterns, or features used to create at least a portion of the microstructure features. In the embodiment shown in FIG. 1B, the masking material includes a plurality of apertures or openings 16 that substantially correspond to the diameter of the microstructures to be formed in the substrate. In some embodiments, the masking material is a stencil, ie, a planar sheet of material into which the desired shapes and patterns have been etched and removed from the sheet. It is to be understood that the apertures or openings in the masking material can be of any desired shape, but will generally correspond to the shape of the outer edge or cross-section of the microstructure being formed. For example, a mask with polygonal apertures or openings (eg, square or rectangular) may result in microstructures having, for example, square, rectangular, or diamond-shaped shapes or cross-sections. The photoresist is cured (18) (step (c)) such that the underlying photoresist exposed by the opening or openings 20 is cured. The photoresist may be cured by any suitable method or methods as known in the art. Exemplary methods of curing photoresists include, but are not limited to, exposure to radiation, including, but not limited to, UV or near UV radiation, deep UV radiation, electron beam radiation, or X-ray radiation. If SU-8 photoresist is used, the photoresist can be cured by exposing the photoresist to light in the near UV spectrum (eg, 350-400 nm).

The masking material and uncured photoresist material are removed by means 22 known in the art, leaving the substrate 10 and hardened photoresist 12 (step (d)). In embodiments, developers, strippers, and/or other solvents as known in the art are used to remove the uncured photoresist. In some exemplary embodiments, the developer is specific for photoresists, such as SU-8 developer available from MicroChem. In other embodiments, the developer may be a solvent-based developer, including, but not limited to, ethyl lactate or diacetone alcohol. The solvent is applied until the uncured photoresist melts. The solvent may be applied by any suitable means. In some non-limiting embodiments, the solvent is applied by at least one of bath-immersing the substrate, spray coating the substrate, and/or dispensing the solvent directly over the top surface of the substrate. Generally, the substrate is incubated with a solvent for a period of time to allow selective dissolution of the photoresist material. In other embodiments, the photoresist may be removed by an oxygen plasma etch process.

The substrate is etched using one or more etching steps. In embodiments, an isotropic etchant 24 is initially used to produce the distal end of the microstructure and/or the inwardly directed portion 26 of the distal tip (step (e)). Generally, an isotropic etchant etches uniformly in all directions such that the portion of the substrate located directly beneath the hardened photoresist is etched and removed both laterally as well as vertically. . In order to know the rate of etching with respect to the etchant, one skilled in the art can formulate the appropriate time of application of the etchant to achieve the desired shape. The isotropic etch may be a wet etch (eg, via immersion in a liquid etchant) and/or a dry (plasma) etch as known in the art. In one embodiment, the isotropic wet etch is followed by an isotropic plasma etch using, for example, SF ₆ , carbon tetrachloride, oxygen, or CHF ₃ or a mixture of any of these gases. .

In embodiments, the substrate is further subjected to etching using an anisotropic etchant (step (f)). In one embodiment, the substrate is subjected to deep reactive ion etching (DRIE). Anisotropic etching is direction dependent. Therefore, the angle or orientation of the etchant source relative to the surface of the substrate determines the angle of etching. For example, as shown in FIG. 1F, DRIE etchant 28 is applied at an approximately 90° angle to the surface of the substrate. The resulting etch creates a structure in the substrate with walls that are approximately 90 degrees to the bottom surface of the substrate. It should be appreciated that the angle of application of the etchant can be adjusted to create microstructures with desired configurations and structures. The cured photoresist material is removed by optional immersion and/or impregnation of the substrate with a suitable solvent or stripping agent (liquid), a suitable solvent or stripping agent, as known in the art. (g)). It is to be understood that the solvent or release agent preferably does not significantly affect the shape of the microstructures formed within the substrate. In some embodiments, the hardened photoresist may be removed by a "drying" method via plasma treatment.

The microstructures are finished using suitable means as known in the art. The finishing step serves to refine and define the desired shape of the microstructure for the mold as well as the array formed therefrom. The finishing step may include refining the microstructure shape, including adjusting an angle for the microstructure and/or finishing a surface of at least a portion of the microstructure. Some exemplary etching steps for finishing are shown in steps (h)-(j) of FIGS. 1H-1J. It should be understood that one or more additional finishing steps may be used. Furthermore, it should be understood that not all of the finishing steps depicted in FIGS. 1H-1J need be used. In one embodiment, one or more of a plasma etch, a wet thermal oxidation step, and/or an isotropic wet etch may be used to finish the surface of the microstructure (step (h )-(j)). In step (h), plasma etching is performed as described above using a suitable gas or mixture of gases, including but not limited to _SF6 . This plasma etch is used to finish the surface and/or correct the angle for the distal tip of the microstructure. It should be appreciated that when using anisotropic etching, the plasma flow can be adjusted to create the desired angle and/or shape, as depicted by 30 and 32. As can be seen in steps (i)-(j), wet thermal oxidation is followed by isotropic etching to create a smooth surface for microstructures and/or sharp edges. Wet thermal oxidation forms a layer 34 of silicon dioxide within the outer surface of the silicon substrate. This layer can be easily removed leaving a smooth surface. One exemplary method of removing the silicon dioxide layer is an isotropic wet etch 36, as shown in step (j). Any suitable wet etching process as known in the art may be used. Wet etching typically involves contacting the material with a chemical etching solution. In some embodiments, the chemical etchant is an acid, including, but not limited to, hydrofluoric acid or phosphoric acid.

As illustrated in FIG. 1K, the resulting microstructured structure 42 has a shaft 40 and a sharp distal tip 38. The shaft length should be long enough to allow skin penetration to the desired depth.

As illustrated in FIG. 2, the positive mold with the microstructured features 42 formed as described above is then used to form a negative mold 46. The negative mold may be formed by any suitable method and/or material as known in the art. In one embodiment, the negative mold is formed by inserting microstructured features into the negative mold material. In other embodiments, negative molds are formed by coating structures of positive mold microstructures with negative mold material. In embodiments, the negative mold material is a polymer. In embodiments, the polymer is a soluble polymer. In embodiments, the polymer is a silicone polymer. In certain embodiments, the polymer is selected from polydimethylsiloxane (PDMS) and copolylactic-glycolic acid (PLGA). The microstructures are removed, leaving a polymer negative mold 46 with cavities 48 in the shape of the microstructure structures 42 of the positive mold.

With continued reference to FIG. 2, negative mold 46 is then used to form a second positive mold, also referred to herein as a master mold, formed from a durable material such as metal. used for. In embodiments, negative mold 46 is coated with a suitable durable material 50. In a non-limiting embodiment, the durable material is a metal selected from copper, gold, nickel, chromium, rhodium, platinum, or alloys thereof. The metal may be coated, applied, or deposited onto the negative mold using any suitable method, including, but not limited to, electroplating, e-beam deposition, and sputter coating. A surplus of metal is applied as indicated by 52 to create the base or proximal region of the microstructure. That is, the durable material is deposited in an amount sufficient to completely fill the cavity within the negative mold and to form the base layer 52 on or over the negative mold. The base can be any suitable thickness 54 depending on the needs of forming the proximal portion of the microstructure. The metal positive mold is removed from the negative mold 46. At this point, the positive mold includes a microstructured shaft with a slab or base layer 52 having a thickness 54 and a distal tip. The base 52 is then machined using any suitable mechanical machining method as known in the art to create the desired shape of the microstructure proximal portion 56. In a preferred embodiment, proximal portion 56 has a funnel or pyramid shape. Any remaining material from negative mold 46 is removed with a suitable solvent such as methylene chloride.

In one exemplary embodiment, the negative mold is formed from silicone, such as polydimethylsiloxane. Negative molds are typically formed by casting liquid mold material over a positive master array. The negative mold cast solution material is allowed to dry and harden. When the cured material is peeled and removed from the cathode material, what is created is a mold with cavities that correspond to the microstructures of the positive master array. It is to be understood that molds suitable for use in the present method may be prepared according to other methods.

One exemplary master array mold includes a plurality of microstructure protrusions having a height of about 100-500 μm. Generally, the master array mold includes a plurality of microstructures having a height of at least about 100 μm, at least about 150 μm, at least about 200 μm, at least about 250 μm, or at least about 300 μm. Generally, it is also preferred that the microstructures of the master array mold have a height of about 1 mm or less, about 500 μm or less, about 300 μm or less, or in some cases about 200 μm or 150 μm or less. In embodiments, the microstructures of the master array mold have a height of at least about 50-500 μm. In other embodiments, the microstructures of the master array mold have a height of at least about 100-500 μm, 100-400 μm, 100-300 μm, 100-200 μm, 100-150 μm, 150-500 μm, 150-400 μm, 150-300 μm. , 150-200 μm, 200-500 μm, 200-400 μm, 200-300 μm, 300-500 μm, 300-400 μm, or 400-500 μm. It is understood that the microstructures within the array can have a range of heights. The microstructures of the master array mold may have any suitable shape, including, but not limited to, polygonal or cylindrical. Particular embodiments include a combination of funnel and cylindrical shapes, with a funnel tip and a cylindrical base, and a conical shape with a polygonal bottom, such as a hexagonal or rhombic shape. Some specific shapes are shown in Figures 3A-3D. Other possible microstructure geometries are shown, for example, in US Published Patent Application No. 2004/0087992 and US Application No. 2014/0180201. In one example, a mold is created to form a microstructure that is shaped like an obelisk, and the distal end of the microneedle shaft is joined and tapered to form a skin-piercing tip. is a pyramid with four angled faces forming a . The pyramid-bearing needle shaft has four planar or flat sides.

In some particular embodiments, the master array includes a plurality of microstructures having a height of about 200 μm, a base of about 70 μm, and an interprotrusion spacing of about 200 μm. In another exemplary embodiment, the master array includes a plurality of hexagonal or other polygon-shaped protrusions having a height of about 200 μm, a base of about 70 μm, and an inter-protrusion spacing of about 400 μm. In yet another embodiment, the master array includes a plurality of cylindrical shaped protrusions having a height of about 400 μm, a diameter of about 100 μm, and an inter-protrusion spacing of about 200 μm. It is to be understood that the cylindrical shaped protrusion may have a funnel shape, a point, or a sharp distal end.

The microstructures of the master mold may be approximately 0-500 μm apart. In specific, non-limiting embodiments, the microstructure of the master mold is about 0 μm, about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, about 400 μm, about 450 μm, or about 500 μm apart. The spacing between microstructures may be measured from the base (base-to-base) or from the tip (tip-to-tip) of the microstructures. The spacing of the microstructures in the master mold may be regular or irregular.

This master mold can then be used to form multiple negative molds of any suitable material. These negative molds can be used in the manufacture of microstructure arrays, where each microstructure contains a therapeutic agent to be administered to a subject for treatment. In one embodiment, the negative mold is referred to as a cast mold because it receives a cast solution or suspension comprising a therapeutic agent. An advantage of this method for providing a cast mold is that the cast mold does not require machining to form the desired shape of the distal and proximal portions of the microstructure. Cast molds may be formed from any suitable material, including polymers and silicone. In one embodiment, the polymer is PDMS, which has the advantages of biocompatibility, viscoelasticity, high chemical inertness, and the ability to adhere to metals, among others. In other embodiments, the casting mold is formed from any natural or synthetic rubber (eg, isoprene, natural rubber, butyl rubber) or polyurethane.
II. How to fabricate microstructure arrays

The method and resulting mold described in Section I above may be used in fabricating microstructure arrays. Exemplary methods are described in U.S. Publication Nos. 2013/0292868 and 2014/0272101 (incorporated herein by reference) in which a casting solution or suspension is deposited onto a negative casting mold. explained. In one exemplary method, microstructure arrays are prepared by casting a polymer matrix solution (or suspension) onto or into a negative cast mold. The solution is dried and the backing polymer solution (or suspension) is cast onto or into a negative cast mold. The backing solution is dried. After drying, the casting mold is removed. Microstructures formed from a dried polymer matrix solution and a dried backing solution result in an array of microstructures consisting of two layers, particularly in embodiments where the two solutions are different.

In one example, the casting solution includes one or more therapeutic agents, active agents, drugs, active pharmaceutical ingredients (APIs), or other substances to be delivered to the subject and one or more polymers. by dissolving or suspending the polymer in a solvent to form a polymer matrix solution or suspension. The terms active agent, therapeutic agent, drug, drug, and API are used interchangeably herein and any discussion or reference to one is intended to include and apply to each and every term. be done. In one embodiment, the casting solution dissolves or suspends at least one drug and one or more polymers in an aqueous buffer or solvent to form a solution or suspension containing the active agent and the polymer. formed by In another embodiment, at least one active agent is dissolved or suspended in a solvent to form an active agent solution or suspension. At least one polymer is separately dissolved in a solvent to form a polymer solution or suspension. Suspensions may be liquid in liquid suspension or solid in liquid suspension, depending on the nature of the active agent and/or polymer. The solvents used for the activator solution and the polymer solution may be the same or different. The active agent solution and polymer solution are mixed to form a polymer matrix solution or suspension. Additionally, it is to be understood that solvent mixtures may be used to dissolve or suspend the active agent and/or polymer.

The casting solvent, in one embodiment, is preferably an aqueous solvent. Suitable aqueous solvents include, but are not limited to, water, mixtures of water and alcohols (eg, C1-C8 alcohols such as propanol and butanol), and/or alcohol esters. In other embodiments, the solvent is non-aqueous. Suitable non-aqueous solvents include, but are not limited to, esters, ethers, ketones, nitrites, lactones, amides, hydrocarbons, and derivatives thereof and mixtures thereof. In other non-limiting embodiments, the solvent is selected from acetonitrile (ACN), dimethyl sulfoxide (DMSO), water, or ethanol. It is to be understood that the choice of solvent may be determined by one or more properties of the active agent and/or polymer. Furthermore, it is to be understood that the casting solvent can comprise a mixture of solvents.

Any suitable drug, therapeutic agent, API, or other active agent can be dissolved or suspended in the solvent. The array is suitable for a wide variety of substances or drugs. Suitable active agents that may be administered include, by way of example and without limitation, resuscitation agents; analgesics; anti-arthritic agents; anti-cancer agents, including anti-tumor agents; anti-cholinergic agents; anti-convulsants; anti-depressants; anti-diabetic agents. antidiarrheals; antiparasitics; antihistamines; antihyperlipidemics; antihypertensives; antiinfectives such as antibiotics, antifungals, antivirals, and bacteriostatic and bactericidal compounds; antiinflammatories; migraine drugs; antiemetics; antiparkinsonian drugs; antipruritics; antipsychotics; antipyretics; antispasmodics; antituberculous drugs; antiulcer drugs; anxiolytics; appetite suppressants; attention deficit disorder and attention deficit hyperactivity Disorders; cardiovascular drugs, including calcium channel blockers, antianginals, central nervous system agonists, beta-blockers, and antiarrhythmics; corrosives; central nervous system stimulants; and common cold drugs, including nasal decongestants. Drugs; cytokines; diuretics; genetic material; herbal remedies; hormonal drugs; hypnotics; hypoglycemic agents; immunosuppressants; keratolytics; leukotriene inhibitors; mitotic inhibitors; muscle relaxants; narcotic antagonists; Includes nicotine; nutritional supplements such as vitamins, essential amino acids, and fatty acids; ophthalmic drugs such as anti-glaucoma drugs; pain relievers such as anesthetics; parasympathetic nerve blockers; peptide drugs; proteolytic enzymes; stimulants; and anti-asthmatic drugs. , respiratory system therapeutics; sedatives; steroids, including progestogens, estrogens, corticoids, androgens, and anabolic agents; smoking cessation agents; sympathomimetics; tissue healing enhancers; tranquilizers; large coronary arteries, peripheral including arteries, and cerebral arteries, including a wide variety of compounds such as vasodilators; vesicants; and combinations thereof.

In embodiments, the active agent is a biological agent, including, but not limited to, a peptide, polypeptide, protein, or nucleic acid (eg, DNA or RNA). In one embodiment, the active agent is a polypeptide, such as human thyroid hormone (eg, hPTH(1-34)), a protein, such as human growth hormone, or an antibody. Examples of peptides and proteins that can be used in conjunction with microstructure arrays include, but are not limited to, parathyroid hormone (PTH), oxytocin, vasopressin, adrenocorticotropic hormone (ACTH), epidermal growth factor (EGF), prolactin, corpus luteum. Formative hormone, follicle-stimulating hormone, luliberine or luteinizing hormone-releasing hormone (LHRH), insulin, somatostatin, glucagon, interferon, gastrin, tetragastrin, pentagastrin, urogastrin, secretin, calcitonin, enkephalin, endorphin, kyotorphin, tuftsin, thymopoietin , thymosin, thymostimulin, thymic humoral factor, serum thymic factor, tumor necrosis factor, colony stimulating factor, motilin, bombesin, dynorphin, neurotensin, caerulein, bradykinin, urokinase, kallikrein, substance P analogs and antagonists, angiotensin II, nerve Growth factors, blood coagulation factors VII and IX, lysozyme chloride, renin, bradykinin, tyrocidin, gramicidin, growth hormone, melanocyte-stimulating hormone, thyroid hormone-releasing hormone, thyroid-stimulating hormone, parathyroid hormone, pancreozymine, cholecystokinin , human placental lactogen, human chorionic gonadotropin, protein synthesis-stimulating peptide, gastric inhibitory peptide, vasoactive intestinal peptide, platelet-derived growth factor, growth hormone-releasing factor, bone morphogenetic protein, and their synthetic analogs and modifications and Includes pharmacologically active fragments. Peptidyl drugs also include synthetic analogs of LHRH, such as, for example, buserelin, deslorelin, fertirelin, goserelin, histrelin, leuprolide (leuprorelin), lutrelin, nafarelin, triptorelin, and pharmacologically active salts thereof. Administration of oligonucleotides is also contemplated and includes DNA and RNA, other naturally occurring oligonucleotides, non-naturally occurring oligonucleotides, and any combinations and/or fragments thereof. As therapeutic antibodies, Orthoclone OKT3 (muromonab CD3), ReoPro (abciximab), Rituxan (rituximab), Zenapax (daclizumab), Remicade (infliximab), Simulect (basiliximab), Synagis (palivizumab), Herce ptin (trastuzumab), Mylotarg (gem tuzumab ozogamicin), CroFab, DigiFab, Campath (alemtuzumab), and Zevalin (ibritumomab tiuxetan).

In other embodiments, at least a portion of the distal layer comprises a drug suitable for use as a prophylactic and/or therapeutic vaccine. In certain embodiments, the vaccine comprises an antigenic epitope conjugated to a carrier protein. It is to be understood that vaccines can be formulated with or without adjuvants. Suitable vaccines include, but are not limited to, anthrax, diphtheria/tetanus/pertussis, hepatitis A, hepatitis B, Haemophilus inruenza b, human papillomavirus, influenza, Japanese encephalitis, measles/mumps/rubella, meninges. inflammatory diseases (e.g., meningococcal polysaccharide vaccine and meningococcal conjugate vaccine), pneumococcal diseases (e.g., meningococcal polysaccharide vaccine and meningococcal conjugate vaccine), polio, Included are vaccines for use against rabies, rotavirus, shingles, smallpox, tetanus/diphtheria, tetanus/diphtheria/pertussis, typhoid, chickenpox, and yellow fever.

In another embodiment, at least a portion of the distal layer comprises a drug suitable for veterinary use. Such uses include, but are not limited to, therapeutic and diagnostic veterinary uses.

Polymers for use in this method are typically biocompatible. In one embodiment, at least a portion of the polymer is biodegradable.

In some embodiments, the polymer is a structure-forming polymer. In certain embodiments, the polymer is a hydrophilic water-soluble polymer. Suitable polymers are known in the art and are described, for example, in US Patent Application No. 2008/0269685. Exemplary biocompatible, biodegradable, or bioerodible polymers include poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(lactic-co-glycolic acid) (PLGA), polyanhydrides. , polyorthoester, polyetherester, polycaprolactone (PCL), polyester amide, poly(butyric acid), poly(valeric acid), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), PEG-PLA block copolymer of PEG-PLA-PEG, PLA-PEG-PLA, PEG-PLGA, PEG-PLGA-PEG, PLGA-PEG-PLGA, PEG-PCL, PEG-PCL-PEG, PCL-PEG-PCL, ethylene glycol - Copolymers of propylene glycol-ethylene glycol (PEG-PPG-PEG, trade name Pluronic® or Poloxamer®), block copolymers of polyethylene glycol-poly(lactic-co-glycolic acid) (PLGA-PEG) , dextran, hetastarch, tetrastarch, pentastarch, hydroxyethylstarch, cellulose, hydroxypropylcellulose (HPC), sodium carboxymethylcellulose (Na CMC), heat-sensitive HPMC (hydroxypropylmethylcellulose), polyphosphazene, hydroxyethylcellulose (HEC), Included are polysaccharides, polyhydric alcohols, gelatin, alginates, chitosan, hyaluronic acid and its derivatives, collagen and its derivatives, polyurethanes, and copolymers and hybrids of these polymers. One hydroxyethyl starch may have a degree of substitution within the range of 0 to 0.9. Exemplary polysaccharides are the dextrans, including Dextran 70, Dextran 40, and Dextran 10.

The casting solution may further include one or more excipients dissolved or suspended in the buffer or solvent. Suitable excipients include, but are not limited to, one or more stabilizers, plasticizers, surfactants, and/or antioxidants.

In one embodiment, one or more sugars are added to the casting solution. The sugar can stabilize the active ingredient and/or plasticize at least one of the polymers. Sugars may also be used to affect, moderate, or modulate the degradation of the polymer. Exemplary sugars include, but are not limited to, glucose, fructose, galactose, maltose, maltulose, isomaltulose, mannose, lactose, lactulose, sucrose, and trehalose, and sorbitol. In other embodiments, sugar alcohols known in the art are included in the casting solution. Exemplary sugar alcohols include, but are not limited to, lactitol, maltitol, sorbitol, and mannitol. Cyclodextrins can also be advantageously used within the microstructure array, such as alpha, beta, and gamma cyclodextrins. Exemplary cyclodextrins include hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin. In other embodiments, when dextran, hetastarch, and/or tetrastarch are used as polymers in the casting solution, sorbitol may preferably be included in the casting solution. In this embodiment, the sorbitol not only stabilizes the active agent, but may also plasticize the polymer matrix, which reduces brittleness. Biodegradability or solubility of microstructure arrays can be facilitated by the inclusion of saccharides. Sugars and sugar alcohols can also be useful in stabilizing peptides, proteins, or other biologically active agents and in modifying the mechanical properties of microstructures by exhibiting plasticizing-like effects. When the active agent is a biological agent, including but not limited to peptides, proteins, and antibodies, one or more sugars or sugar alcohols are used in the casting solution as a stabilizing agent. It's okay. The saccharide can be added to (i) the therapeutic solution or suspension, (ii) the polymer solution or suspension, or (iii) once (i) and (ii) are mixed, the polymer matrix solution or suspension. May be added.

One or more surfactants may be added to the casting solution to change the surface tension of the solution and/or reduce hydrophobic interactions of proteins. Any suitable surfactant as known in the art may be used. Exemplary surfactants include, but are not limited to, emulsifiers such as Polysorbate 20 and Polysorbate 80.

One or more antioxidants may be added to the casting solution. Any suitable antioxidant as known in the art may be used. Exemplary antioxidants include, but are not limited to, methionine, cysteine, D-alpha tocopherol acetate, EDTA, and vitamin E.

In one embodiment, an optional backing layer, base layer, or substrate is further cast onto the mold. A liquid backing formulation is dispensed onto the mold or into the cavity. Liquid backing formulations are typically prepared by dissolving or suspending one or more polymers in a suitable solvent. In preferred embodiments, the one or more polymers are biocompatible. Typically, but not always, polymers are non-biodegradable. In another embodiment, the backing formulation may consist of one or more biodegradable and/or non-biodegradable polymers. Suitable biodegradable polymers are those mentioned above. Suitable non-biodegradable polymers are known in the art and include, but are not limited to, amphiphilic polyurethane, polyether polyurethane (PEU), polyether ether ketone (PEEK), poly(lactic acid-co-glycol) (PLGA), polylactic acid (PLA), polyethylene terephthalate, polycarbonates, acrylic polymers such as those sold under the trade name Eudragit®, polyvinylpyrrolidone (PVP), polyamideimide (PAI), and/or or a copolymer thereof. Further suitable polymers are described in US Pat. No. 7,785,301, incorporated herein in its entirety. In another embodiment, the backing layer is an adhesive layer. One suitable adhesive is Dymax® 1187-MUV medical device adhesive. It is to be understood that any biocompatible adhesive is suitable for use with, in, and/or as the backing layer. This layer may also be a nonwoven or porous film coated on both sides with a pressure sensitive adhesive. The liquid backing formulation may be transferred into the cavity by the same or similar method as for the active agent casting solution. If a liquid backing layer formulation is used, the solvent of the backing layer formulation is removed by a drying process. The drying conditions for drying the backing layer are such that the backing layer solvent is effective without affecting the stability of the active agent and/or to properly form a (e.g., uniform) backing layer. It should be controlled so that it can be removed permanently. In one embodiment, the mold is placed in a compressed dry air (CDA) box under controlled airflow and then placed in an oven at about 5-50°C. In a further embodiment, the mold is placed in an oven at a temperature of about 5-50°C. In embodiments, the CDA and/or furnace temperature is about 5°C, about 10°C, about 20°C, about 30°C, about 40°C, about 45°C, or about 50°C. In embodiments, the temperature of the CDA and/or furnace is about 5-45°C, 5-40°C, 5-30°C, 5-20°C, 5-15°C, 5-10°C, 10-50°C, 10°C. ～45℃, 10～40℃, 10～30℃, 10～20℃, 10～15℃, 15～50℃, 15～45℃, 15～40℃, 15～30℃, 15～20℃, 20 ~50℃, 20-45℃, 20-40℃, 20-30℃, 30-50℃, 30-45℃, 30-40℃, 30-45℃, 40-50℃, 40-45℃, or The temperature is 45-50°C. In embodiments, the oven uses convection, conduction, or radiation for drying. In another embodiment, the mold is placed in an oven at about 5-50° C. without any lead time in a CDA box. In embodiments, the mold is heated for at least about 0 to 120 minutes, about 30 to 120 minutes, about 30 to 90 minutes, about 30 to 60 minutes, about 30 to 45 minutes, about 45 to 120 minutes, about 45 to 90 minutes. , about 45-60 minutes, about 60-120 minutes, about 60-90 minutes, about 90-120 minutes, or longer in the CDA and/or furnace. Residual solvent within the backing layer can be measured to determine the effectiveness of solvent removal under different drying conditions. The backing layer connects and/or supports the microstructure tips.

FIG. 4 is an illustration of a method of forming a microstructure with a drug-in-tip (DIT) and a backing layer. A negative cast mold is created from the master mold, described in Section 1. A liquid DIT casting solution is deposited into a negative casting mold, which naturally has at least one cavity in the desired shape for the microstructure. The liquid DIT solution is dried under controlled conditions to remove the solvent and thus create a solid DIT layer at the bottom or distal end of the cavity. A backing layer is cast onto the mold over the solid DIT layer so that the remaining space within the cavity is filled and optionally a layer of the backing layer formulation extends between adjacent cavities. Ru. The backing layer is dried such that the resulting array has a backing layer with a plurality of microstructures extending at an angle from the backing layer. The backing layer with attached microstructures is demolded and subjected to a final drying step to form a microstructure array (MSA). It is to be understood that the MSA may be demolded prior to undergoing a final drying step.

The microstructures may be positioned on a base or substrate to form an array. A substrate may be added to or used in conjunction with the backing layer. The microstructures may be attached to the substrate by any suitable means. In one non-limiting embodiment, the microstructures are attached to the substrate using an adhesive. Suitable adhesives include, but are not limited to, acrylic adhesives, acrylate adhesives, pressure sensitive adhesives, double-sided adhesive tapes, nonwoven or porous films coated with adhesive on both sides, and UV-curable adhesives. can be mentioned. One exemplary double-sided tape is #1513 double-sided coated medical tape available from 3M. One exemplary, but non-limiting UV curable adhesive is 1187-MUV photocurable adhesive available from Dymax. It is understood that any medical device adhesive known in the art would be suitable. In one embodiment, the substrate is a breathable nonwoven pressure sensitive adhesive. The substrate, if present, is placed on the backing layer or on the proximal surface of the microstructure. The substrate is glued or attached to the microstructure. In another embodiment, the substrate is a UV cured adhesive within a polycarbonate film. The UV adhesive is dispensed onto the top of the backing layer or the proximal surface of the microstructure, covered with a polycarbonate (PC) film, and the adhesive is spread and cured using a UV fusion system. In one embodiment, the UV curing dose is about 1.6 J/ ^cm2 . After the substrate is attached or adhered to the microstructures, the microstructure array is removed from the mold. It should be appreciated that if the array includes a backing layer, the substrate is attached or adhered to the backing layer as described above with respect to microstructures.

The cast microstructure array is removed from the mold by any suitable means. In one embodiment, the microstructure array is removed from the mold by using a demolding tool. A double-sided adhesive is placed on the back of the microstructure array with one side for adhering to the array and the other side for adhering to the demolding tool. The array is removed from the mold by gently rolling the release tool across the adhesive on the back of the array. The microstructure array is then removed by gentle peeling from the demolding tool. The array may be demolded after drying the backing layer or after a final drying step.

A final drying step may be performed under vacuum before or after the microstructure array is removed from the mold. Final drying may be at room temperature or elevated temperature. In embodiments, the final drying is about 5-50°C. In embodiments, the final drying is about 5°C, about 10°C, about 20°C, about 25°C, about 35°C, about 40°C, about 45°C, or about 50°C. Further suitable temperatures and ranges are described above with reference to drying the backing layer. In embodiments, the final drying is for about 1 to 24 hours or longer, about 4 to 20 hours, about 6 to 10 hours, about 8 to 16 hours, about 8 to 12 hours, about 8 to 10 hours, about 10 to 12 hours, about 10-16 hours, about 12-16 hours or longer. In other embodiments, the final drying step is overnight.

After the microstructure array is removed from the mold, it may be cut to the appropriate size and/or shape. In one embodiment, the microstructure array is die cut using an 11 or 16 mm punch.

Figure 5 outlines the steps for forming a negative cast mold used to prepare a master mold of durable material and use the master mold to prepare a microstructure array. , depicting the overall process.
III. microstructure array

General characteristics of microstructure arrays suitable for use in the present arrays and methods are described in U.S. Patent Publication No. 2008/0269685, U.S. Patent Publication No. 2011/0006458, and U.S. Patent Publication No. 2011/0276028 (in its entirety). (herein expressly incorporated by reference).

The microstructure array is preferably both stable during the fabrication process as described above and has a stable shelf life. The short-term stability of the arrays was determined by storing the arrays at various temperatures and/or humidity and determining monomer content, composition purity, and composition purity by SEC-HPLC, RP-HPLC, and IEX-HPLC, respectively, at specific time points. It can be assessed by analyzing protein deamidation. The liquid casting solution or formulation is preferably stable during the fabrication process, which typically lasts several hours. Preferably, the liquid casting solution is stable over a period of 30 minutes to 6 hours. In non-limiting embodiments, the liquid casting solution is applied for at least 30 minutes to 1 hour, 30 minutes to 2 hours, 30 minutes to 3 hours, 30 minutes to 4 hours, 30 minutes to 5 hours, 1 to 6 hours, 1 ~5 hours, 1-4 hours, 1-3 hours, 1-2 hours, 2-6 hours, 2-5 hours, 2-4 hours, 2-3 hours, 3-6 hours, 3-5 hours, 3 Stable over periods of ~4 hours, 4-6 hours, 4-5 hours, or 5-6 hours. In specific, non-limiting embodiments, the liquid casting solution is applied for at least about 30 minutes, about 45 minutes, about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours. stable over time or over longer periods of time. The microstructure array is preferably stable for at least about one day when stored at about room temperature (eg, about 25° C.). In other embodiments, the array can be stored at room temperature for at least a period of time after fabrication. In some embodiments, the array is preferably stable for at least about 1-12 weeks, about 1-16 weeks, or about 1-32 weeks when stored at about 5°C. In other embodiments, the array is stable for at least about 1-12 weeks, about 1-16 weeks, or about 1-32 weeks when stored at elevated temperatures (eg, about 40° C.). In other embodiments, the array is stable for at least about 1-52 weeks or 1-156 weeks when stored at about 5°C. It is understood that shelf life may vary depending on storage temperature. In embodiments, the array, when stored at about 5° C., is stored for at least about 1-156 weeks, about 1-12 weeks, about 1-2 weeks, about 1-3 weeks, about 1-4 weeks, about 1-156 weeks, about 1-12 weeks, about 1-2 weeks, about 1-3 weeks, about 1-4 weeks, about 1-156 weeks 5 weeks, about 2-6 weeks, about 2-5 weeks, about 2-4 weeks, about 2-3 weeks, about 3-6 weeks, about 3-5 weeks, about 3-4 weeks, about 4-6 weeks , stable for about 4-5 weeks, or about 5-6 weeks. In embodiments, the array is stored for at least about 1-26 weeks, about 1-12 weeks, about 1-2 weeks, about 1-3 weeks, about 1-4 weeks, about 1-26 weeks, about 1-2 weeks, about 1-3 weeks, about 1-4 weeks, when stored at about 40°C. 5 weeks, about 2-6 weeks, about 2-5 weeks, about 2-4 weeks, about 2-3 weeks, about 3-6 weeks, about 3-5 weeks, about 3-4 weeks, about 4-6 weeks , stable for about 4-5 weeks, or about 5-6 weeks. In other embodiments, the array is stable for at least about 1-14 days when stored at about 25°C. In further embodiments, the array is stable for at least about 1-12 weeks, about 1-16 weeks, about 1-104 weeks, or about 1-156 weeks when stored at about 25°C. In specific, non-limiting embodiments, the arrays, when stored at about 5° C., last for at least about 5 days, at least about 1 week, at least about 2 weeks, at least about 4 weeks, at least about 5 weeks, Stable for at least about 6 weeks, or longer. In embodiments, the array is stored for at least about 1-2 days, about 1-5 days, about 1-7 days, about 1-10 days, about 2-5 days, about 2-5 days when stored at about 25°C. 7 days, about 2-10 days, about 2-14 days, about 3-5 days, about 3-7 days, about 3-10 days, about 3-14 days, about 5-14 days, about 5-10 days , stable for about 5-14 days, or about 10-14 days. In specific, non-limiting embodiments, the array, when stored at about 25° C., will last for at least about 12 hours, at least about 1 day, at least about 2 days, at least about 3 days, at least about 4 days, Stable for at least about 5 days, at least about 6 days, at least about 1 week, or longer. Stability is typically monitored by measuring the purity of the active agent within the array after storage compared to the array before storage (time=0). In embodiments, the array is at least about 80-100%, about 85-100%, about 90-100%, about 95-100%, about 80-95%, about 85-95%, about 90-100% after storage. 95% has a purity of about 80-90%, about 85-90% or about 80-85%. In non-limiting embodiments, the array after storage is at least about 80%, about 85%, about 90%, about 92%, about 93%, about 95%, about 96%, about 97%, about 98%, It has a purity of about 99%, or about 100%.

When the active agent is a protein, methionine oxide (Met oxide) is preferably less than or equal to 1-20% after storage at about 5°C to 40°C for about 1-6 weeks. In embodiments, the Met oxide is about 1-10%, about 1-5%, about 1-6%, about 2-3%, about 2-4%, about 2-5%, 2-6%, about 3-5%, or less than about 3-6%. In specific, non-limiting embodiments, the Met oxide is less than about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, or about 10%.

The microstructure array should have sufficient mechanical strength to at least partially penetrate the stratum corneum or other membrane surface of the subject. It is understood that different mechanical strengths may be required for applications at different sites. One method to assess mechanical strength is a skin penetration efficiency (SPE) study as described in Example 7. Preferably, the array has an SPE of about 50-100%. In other embodiments, the array is about 50-80%, about 50-85%, about 50-90%, about 50-95%, about 60-80%, about 60-85%, about 60-90% , about 60-95%, about 60-100%, about 75-80%, about 75-85%, about 75-90%, about 75-95%, about 75-100%, about 80-85%, about having an SPE of 80-90%, about 80-95%, about 80-100%, about 90-95%, and about 90-100%. In specific non-limiting embodiments, the array has an SPE of about 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, and 100%.

Preferably, at least about 50-100% of the active agent is delivered by the MSA described herein. Delivery efficiency can be determined by preparing MSA and applying the MSA in vivo or in vitro, as described in Example 7. In embodiments, the MSA is at least about 50-60%, about 50-70%, about 50-75%, about 50-80%, about 50-90%, about 50-95%, about 50-99%, about 60-70%, about 60-75%, about 60-80%, about 60-90%, about 60-95%, about 60-99%, about 70-75%, about 70-80%, about 70 ~90%, approximately 70-95%, approximately 70-99%, approximately 75-80%, approximately 75-90%, approximately 75-95%, approximately 75-99%, approximately 80-90%, approximately 80-95 %, about 80-99%, about 90-95%, about 90-99%, or about 95-99%.
IV. how to use

The methods, kits, microstructure arrays, and related devices described herein can be used to treat any condition. Microstructure arrays are described in the applicators described in U.S. Patent Publication No. 2011/0276027 and in U.S. Application Nos. 2014/0276580 and 2014/0276580, each of which is incorporated herein in its entirety. It should be understood that it may be used in conjunction with any suitable applicator, including those that

While some example aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, permutations, additions, and subcombinations thereof. It is therefore intended that the following appended claims and the claims hereafter introduced include all such modifications, permutations, additions, and subcombinations as are within their true spirit and scope. intended to be interpreted.

All patents, patent applications, and publications mentioned herein are incorporated by reference in their entirety. However, if a patent, patent application, or publication document containing explicit definitions is incorporated by reference, those explicit definitions apply to the patent, patent application, or publication document in which they are found or incorporated. It is understood that the definitions provided herein are not necessarily applicable to the present application, and in particular to the language of the claims herein, in which case the definitions provided herein are meant to take precedence. sea bream.

Claims (26)

A method of forming a master mold, the method comprising:
a) forming a plurality of microstructured portions in a substrate formed from a first material by a first micromachining process, each microstructured portion comprising a shaft and a distal tip; step and
b) preparing a negative mold for the plurality of microstructures, the negative mold being formed from a second material, the negative mold forming a negative mold for each microstructure in the plurality of microstructures; a step comprising a plurality of cavities corresponding to the structural portion;
c) electroplating metal onto the negative mold to fill each cavity in the plurality of cavities to form a base layer extending from the negative mold;
d) forming a proximal section for each of the plurality of microstructured portions in the base layer using a second micromachining process;
e) forming a master mold by removing the negative mold from the metal before or after step d). 2. The method of claim 1, wherein the second micromachining process is a mechanical micromachining process. 3. The method of claim 1 or claim 2, wherein the first material is selected from silicon and a positive photoresist material. A method according to any one of claims 1 to 3, wherein the first micromachining process comprises a photolithography process. The photolithography process includes:
1) applying a layer of photoresist on the first material;
2) applying a masking material on the layer of photoresist, the masking material covering at least a portion of the layer of photoresist;
3) curing portions of the layer of photoresist not covered by the masking material;
4) creating the distal tip by isotropically etching the substrate;
5) creating the shaft by etching the substrate;
6) Wet thermal oxidation of the plurality of microstructure parts;
7) isotropically wet etching the plurality of microstructured portions. 6. The first material is silicon, and the method further comprises forming a layer of silicon dioxide on a silicon substrate using a thermal oxidation process prior to step 1. the method of. 7. The method of claim 6 , wherein the thermal oxidation process used prior to step 1 is a wet thermal oxidation process. 6. The method of claim 5, wherein the photoresist material is an epoxy-based negative photoresist. 6. The method of claim 5, wherein the masking material comprises a plurality of apertures and the layer of photoresist exposed by the plurality of apertures is cured in step 3. 6. The method of claim 5, wherein the method further comprises removing the masking material and any uncured photoresist material after step 3. 11. The method of claim 10, wherein the masking material and uncured photoresist are removed using a solvent. 6. The method of claim 5, wherein the etching of step 5 comprises anisotropic etching. 6. The method of claim 5, wherein step 5 comprises deep reactive ion etching. 6. The method of claim 5, wherein the method further comprises the step of cleaning the polymeric material prior to step 1. 15. The method of claim 14, wherein the cleaning comprises chemical cleaning. 16. The method of claim 15, wherein the chemical cleaning comprises an RCA cleaning process. 6. The method of claim 5, wherein step 4 and/or step 5 comprises plasma etching. 18. The method of claim 17, wherein the plasma etching comprises a plasma gas selected from _SF6 , carbon tetrachloride, oxygen, _CHF3 . 6. The method of claim 5, wherein the method further comprises removing any remaining photoresist from the first material after step 5. A method according to any preceding claim, wherein the second material is a polymeric material. A method according to any one of claims 1 to 20, wherein the second material is a silicone material. 21. The method of claim 20, wherein the polymeric material is selected from the group consisting of polydimethylsiloxane (PDMS), polycarbonate, polyetherimide, polyethylene terephthalate. 23. A method according to any one of claims 1 to 22, wherein the metal is selected from copper, nickel, chromium, gold. 24. A method according to any preceding claim, wherein the proximal section is micromachined to have a funnel or pyramid shape. 25. A method according to any one of the preceding claims, wherein the method further comprises the step of preparing a negative mold of the master mold, thereby forming a casting mold. 1. A method of preparing a microstructure array, the method comprising:
forming a casting mold according to the method of claim 25;
dispensing a polymer matrix solution or suspension containing at least one therapeutic agent onto the casting mold;
drying the polymer matrix solution;
dispensing a polymer matrix backing solution onto the casting mold;
forming the microstructure array by drying the polymer matrix backing solution;
demolding the microstructure array.

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